Antiviral agents having a guaninyl substituent on a carbohydrate surrogate are known. For example, the compound [1R- (1.alpha.,2.beta.,3.alpha.)]-2-amino-9-[2,3-bis (hydroxymethyl)cyclobutyl]-1,9-dihydro-6H-purin-6-one, i.e., ##STR2## is an antiviral agent with activity against herpes simplex virus type 1 and 2, varicella zoster virus, human cytomeglavirus, vaccina virus, murine leukemia virus, and human immunodeficiency virus.
Bisacchi et al. in U.S. Pat. No. 5,064,961 disclose preparing this antiviral agent by reacting a bis(2,3-protected hydroxymethyl)cyclobutane of the formula ##STR3## wherein X is a leaving group and R.sup.4 is a protecting group with a protected guanine such as 2-amino-6-benzyloxypurine, 2-amino-6-methoxyethoxypurine, 2-amino-6-chloropurine, or 2-acetamido-6-hydroxypurine in the presence of a base such as potassium carbonate or sodium hydride in a solvent such as dimethylformamide at from about 40.degree. C. to 150.degree. C., preferably 100.degree. to 120.degree. C. for 4 to 48 hours. Removal of the R.sup.4 protecting groups and the guanine protecting group yields the desired antiviral agent.
Slusarchyk et al. in U.S. Pat. No. 5,126,345 disclose a similar process to prepare the racemic compound (.+-.)-(1.alpha.,2.beta.,3.alpha.)-2-amino-9- [2,3-bis(hydroxymethyl)cyclobutyl]-1,9-dihydro-6H-purin-6-one.
Ichikawa et al. in European Patent Application 358,154 disclose reacting a cyclobutane of the formula ##STR4## wherein X is a leaving group and R.sup.4 is hydrogen or a protecting group with a nucleic acid base including 2-amino-6-chloropurine in the presence of a basic catalyst. Ichikawa disclose the preparation of [1R-(1.alpha.,2.beta.,3.alpha.)]-2-amino-9-[2,3-bis(hydroxymethyl)-cyclobu tyl]-1,9-dihydro-6H-purin-6-one.
Norbeck et al. in U.S. Pat. No. 5,153,352 also disclose the preparation of [1R-(1.alpha.,2.beta.,3.alpha.)]-2-amino-9-[2,3-bis(hydroxymethyl)- cyclobutyl]-1,9-dihydro-6H-purin-6-one.
Hagberg et al. in European Patent Application 55,239 and Zahler et al. in European Patent Application 458,363 disclose the tetrabutylammonium salt of 2-amino-6-benzyloxypurine.